1. Field of the Invention
The present invention relates to apparatus for spreading granular and liquid materials on road surfaces. More particularly, the invention relates to a granular material spreader and liquid material dispenser mounted on a vehicle for the synchronous dispensing of solid and liquid thawing materials onto a road surface.
2. Description of the Prior Art
Spreader vehicles or spreader implements for distributing ice thawing and traction enhancing materials on roads are known. Such spreader vehicles have a granular material hopper and delivery system, and can include a liquid delivery system, wherein a gravity feed system or a liquid pump supplies thawing liquid from a tank carried by the vehicle. A granular and liquid material spreader is shown in W. Kupper, U.S. Pat. No. 4,442,979. The Kupper patent also shows synchronized delivery of both liquid and granular materials according to the speed of travel of the vehicle, an example of ground speed control. Kupper can deliver only liquid, only granular material or a combination of the two, all proportional to the speed of the vehicle.
Another spreader apparatus known in the art comprises a spreader for granular and liquid materials comprising a vehicle including a hydraulic system, a storage hopper mounted on said vehicle for containing granular material, a granular material delivery apparatus including a conveyor driven by said hydraulic system for moving the granular material from the hopper to a delivery position and means at said delivery position for receiving and distributing said granular material onto the roadway surface, a controller for controlling the speed of said conveyor, means for sensing conveyor speed and generating a conveyor speed signal, a liquid storage tank mounted on said vehicle, a liquid material delivery apparatus including a conduit for supplying liquid material from said tank to a delivery position and means at said delivery position for distributing said liquid. This apparatus has been sold and commercially distributed under the tradename EPOKE.